Liquid-supply system



March 1o, 1925. 1,529,070

J. M. LEA

LIQUID SUPPLY SYSTEM Filedyqv. 29, 1920 2 sheets-sheet 1 @noa/nto@ Y /f -i' ozmm! go@ ed 5 www March l0, 1925. 1,529,070

J. M. LEA

LIQUID SUPPLY SYSTEM Filed NOV. 29A, 1920 2 Sheets-Sheet 2 @51j 5 africane/uf Pefeetea Mer. 1o, 192s.

aJNITED STATES JOHN n. LEA, or nETnoIn-mcnman.

LIQUID-SUPPLY svsmmr.

application alea November 29,1920. serial No. 427,345.

To all 'whom 'it maycm'zcem:

Be it known that I, JOHN M.' LEA, a citizen of the United States, and a resident of Detroit, county of Wayne, and State of Michigan, have invented certain new and useful Improvements in Liquid-Supply Systems, of which the following isa full, clear, concise, and exact description, such as will enable others skilled in. the art to which the invention relates to make and use the same, reference being made therein to the accompanying drawings, which form a part of this specification. y

rllhe invention relates to liquid level maintaining and indicating means and may have especial utility in connection with watercooled internal combustion engines, and more particularly with those which form a part of the power plant of motor vehicles, such as aeroplanes, tractors, trucks, and passenger automobiles.

rlhe invention has for its 'principal object the improvement of liquid cooling apparatus of the type above referred to in which sub-atmosphere pressure is utilized within the radiator for filling in one or more of the following respects:

1. By the provision of means for maintaining the level of cooling liquid in the liquid cooling receptacle or heat radator of the system at a substantially constant'. point such that the said receptacle is in eliect completely filled or vthe level held at a point vtlaln higher than is normally considered 2. By the provision of means whereby the level of cooling liquid and the physical effect of abnormal temperature conditions in the radiator may be observedby the operator `preferably from the drivers sta-tio or seat.

3. By the provision of means attached to the radiator, per se, and preferably applicable to the filling opening or cover thereof.

whereby the pressure Within the radiator is controlled.

4. By the provision of arelatively inex-I modilication, and, if desired, without necessitating the piercing of the radiator walls.

5. By the provision of means whereby the li uid supply system may be so arranged that t e vapors generated in the radiator may be condensed and retained in the cooling system, liquid being fed to the radiator from a reserve supply while the engine is in operation to maintain the level substantially constant. v

6. By the provision of means whereby the vapors generated in the radiator may be frequently removed by suction, but by condensation and subsequent trapping of said condensed vapor in an auxiliary vessel, is substantially prevented from entering the suction producing device and means for returning this liquid to the circulating system upon return of atmospheric conditions in said auxiliary tank as a resultv of stoppage of said device.

The invention has for a further object the provision of an improved liquid level maintaining device and indicating means especially -useful therewith and generally aplicable to systems or receptacles wherein 1t is desirable to maintain a substantially constant level of liquid.

With the above and other objects in view as will appear more fully from the follow- .ing description, the. invention comprises the features of novelty herein described, to-

gether with such variations and modifications as fall within the scope of the appended claims.

In the accompanying drawings: Fig. 1 is an elevation partially in section showing the invention applied to a common form of automobile engine;

Fig. 2 is a sectional elevation taken through the radiator cap shown in Fig. 1;

Figs. 3 and 4 are sectional elevations showing modified forms of the controlmech anism mounted in the radiator; and` Fig. 5 is a sectional view showing the.

construction of the supply tank valve.

Referring to the embodiment of the invention shown in Figs. 1 and 2v, 10 indicatesv an internal combustion engine, which may be any usual or desired form of engine of the water-cooled type, having an intake conduit or manifold 11 designed to convey explosive mixture to the engine cylinders. The heat radiator 12, which may be of any type adapted to dissipate heat from a cooling liquid, is shown as of a form commonly employed in automobiles and situated in front of the eng`ne at the forward end of the hood 13. The radiator comprises a top header 14 connected to the water jacket of the engine by a pipe 15, similar provision being made at the bottom of the radiator for the return of cooling liquid to the engine, the circulation being induced. by thermo-siphonic action or otherwise in the usual manner.

At the top of the cooling receptacle, shown as the radiator casing or header 14, is a reduced portion comprising a neck 16 which provides preferably a filling opening for the radiator and is screw-threaded to receive a cap or closure 17. In order to render visible to the operator the conditions within the cap, I provide the latter with a transparent portion which may take the form of aglass dome 18 arranged to be secured4 witlun-a recess formed 1n the semi-spherical member 1 9 b v formed members 20 and sectional ribs 21, formed uponthe inner surface of the transparent portion 18, and held in substantially air-tight relation to the member 19 by .the resilient gasket 22. The glass dome 18 may be inserted into said recess when the sectional ribs 21 register with the spaces between the curved portions23 of the members 20. 'Then by pressingthe dome against the gasket 22 and turning the vdome relatively' to the member 19 the curved portions 23 will engage over the ribs 21 and thereby retain the parts in -assembled relation. Attached to or forming part of the member 19 is the hollow threaded member 24 which is inserted into a hole drilled in the radiator cap 17 and secured in practically airtig rht relation by gaskets 25 and 26, washer 27, and'nut 2S, the cap being secured in practicallyair-tight relation in the usual manner by turning the cap 17 down upon the screw-threaded neck 16 and washer 29. The member 24 has a bore which permits passage of liquids or gases between the dome-shaped enclosure and the radiator Upon thespi-ders 36 and 37 is mounted the tubular oat support. 38 which is aligned with the passage 35 b y the spiders and is further held in" position by wire clampwashers 39 and 40. This arrangement permits the whole valve mechanism. to turn freely while screwing down the 'cap 17 preventing distortion of the flexible connection`41 whlch is an extension of suction conduit 32 and is preferably of the maindicated by Fig. 1, this flexible connection is made long enough to permit .the removal of cap 17 without disconnection but can readily be disconnected from tubular support 38 if desired. Tubular support 38 communicates at its upper end with the space over the cooling system liquid but such communication is controlled by valve 42 acting upon its seat in plug member 43 which is preferably sealed into support 38. This `valve is actuated by float 44 which is guided by the tubular support 38, ioat 44 being in this case constructed of metal, as is common to the art, having a' center sleeve 47 which projects beyond thelimits of the float wall and carries a formed member 45 through which cooling liquid may enter the radiator.

'I`l1e' conduit 30 leads to a reserve tank or auxiliary supplyreservoir 31 which.A may be secured in any convenient position upon f or adjacent to the engine but preferably below the top of the radiator so thatliquid will not tend to overow the radiator from the auxiliary tank when the radiator cap is removed. It is not materialy where the conduit 30 enters the radiator, nor is it essential that it extend toa point within the filler opening as shown. In linstalling the apparatus in connection with ordinary motor vehicle power plants, however, it is convenient to utilize forthe `conduit' 30 the usual radiator overflow pipe, and I have so illustratedl the construction inthe drawing, the overflow pipe in this case being merely shortened and connected at its lower end to the tank-31 as, for example, by means of a short length of rubber hose'and clamps.

A suction conduit 32 also extends into the radiator and has its end open at apoint near` the highest portion thereof. It also extends through the supplyv tank 31 and its other end is sealed into the upper portion thereof but opens in to the auxiliary tank i gine intake manifold 11. In order to avoid piercing the radiator walls the conduit 32 may be inserted through the conduit as indicated in Figs. 1 and 3.

The auxiliary tank 31v may be provided with a. suitable removable cap to permit filling of the same independently of the radiator, althou h, lwith the arrangement of parts shown 1n Fig. 1 the tank maybe filled by overflow from the radiator through conduit 30. An leads from the' upper portion of tank 31 to any suitable point of discharge. This connection is open to the atmosphere` and insures the maintenance of atmospheric pressure above the liquidin the supply tank.

Connecting the auxiliary tank 33 and supply tank 31, which may be two separate tanks with a check valve of the usual form or a partitioned tank which is the preferred form, as shown, is a valve controlled passage which may be formed in a member 49 as shown on an enlarged scale in Fig. 5. rlhis member is preferably of metal and of such a. thickness that it can be stamped out' of sheet material in approximately the form shown.

Intersecting drilled holes 52 and 53 form a -V-shaped path which will be closed below the intersection, against water leakage, in the position shown, so as to maintain a liquid seal for the valve 51 upon the seat formed by enlarging the hole v52 at its upper end. The upper portion of this member projects through the common wall of tanks 31 and 33 and is sealed therein preferably by sldering. The part of the member 49 through which the passage 52 opens is spaced slightlyv from the upper wall of tank 31, thus per- Initting low from tank 33 to tank 31 so that when atmospheric pressure is restored in tank 33 as by the stoppage lof the suction device, any liquid which has been condensed and discharged into tank 33 will flow by gravity into tank 31 which is also at atmospheric pressure. When the pressure in tank 33 is sub-atmospheric the valve 51 prevents air leakage from tank 31, the pressure of which is generally atmospheric by reason of the communication of conduit 48--with the this form of cap may not provide sufficient atmosphere. Valve 51 is greater in length than the space between the end openin of passage 52 and the wall common to th tanks which latter `therefore acts as a stop for the valve. The opening of passage 52 is preferably close to the upper wall of tank '31 and above the opening 1n over-flow pipe 48 so that in case valve 51 should fail to close the tank 33 will not be caused to fill -With liquid and consequently be discharged into the engine through conduit 34 and the intake manifold 11.

In the form illustrated in Fig. 3 a tubu lar post 54 is carried by a'plate55 supported by and attached to the gasket 56 as by the overflow connection 48 struck-up points 57. The lower end of the post is connected by iexible tubing 41 to the upper end of the suction conduit 32 thus permitting the withdrawal of the gasket 56 and the parts supported thereon, when desired, to facilitate the filling o f the radiator.

In` aninteriory screw-threaded recess in the upper end o the post 54 is mounted a valve body 58 provided at its lower end with a valve seat adapted to coo crate with a body 58 and carries two stops formed by flattening the stem, the lower one of which may be omitted if the opening ofthe valve by the float be regarded as unnecessary. A lioat 60, which may be of any suitable mavalve 59. Thel stem of the va ve 59 extends upwardly through a passage in the valveA terial commonly employed for this purpose but is shown as of cork, is mounted around the post 54 to be guided vertically thereby. A sleeve or lining 61 may surround'the central aperture of the cork, and carried by the float, as by connection to the lining 61, is a valveactuatin member comprising a perforated'plate tting Iloosely about7 the stem of valve 59 between the stops sliown. The ,disc may be perforated as at 62 to provide communication lbetween the valve and the upper space, within the cap or dome, which perforations may be so arranged as to permit the insertion of a Spanner or slotted screw-driver to engage -a slot in the valve body 58 when desired to assemble or dis# assemble the parts.

In this form the transparent cap member may be constituted by the glass dome 63 secured to a metal ring 64 having a flange 65 which may be clamped upon the gasket 56 by the viller cap 17', the latter being pro- .vided with a central aperture through which the dome projects. Y

the wall of the header 14 independently ofl y the conduit 30. The cap 66 may be the ordinary radiator filler cap, the transparent portion being dispensed within this case. `The plate 67 in this 4instance carries the tubular post .68 depending therefrom, since space for the valve mechanism to be supported abovethe gasket 56.

' A valve 70 is arranged within the post 68, the valve stem extending upwardly and being provided with the stop 71 and, if devsired, the stop 72. A bridge 73 supported uponI the oat 74 Vby studs 75 fits loosely about the valve step between the stops 71,

72, and serves to seat or unseat the valve as the float rises or falls. Since the valve mechanism is supported upon the gasket 56 it may be removed from the filler opening upon removal ofthe cap.-

The operation of the structure described is as follows:

' If now the engine be started the partial vacuum produced in the engine intake conduit or manifold will -be communicated through pipes 34 and 32 to the upper portion of the radiator thereby causing liquid to may be seen from'thedrivers seat.

flow from the reserve tank through pipe 30 until the float risesand closes the valve, at which time, `ifv the transparent cap or dome is employed as indicated, the liquid l At this time the level of liquid will be above the outlet of the overflow or supply conduit 30 and the pressure in the dome will be suiciently below atmosphericpressure to vbalance a column of liquid of a height equal to the difference between the levels in the radiator and the reserve tank.

When the cooling liquid becomes suffi-l ciently warm to begin to vaporize, the evolution of vaporwill relievethe vacuumto a certain extent thereby permitting the level of liquid to fall until the float operates to open the valve and thus re-establish communication with the engine intake.

, Vapor drawn off through the suction con-4 duit 32 will be condensed therein due to its large superficial area relatively. to its volume and to the-cooling effect 'of the medium vin tank 31 and conduit 30 through which the conduit 32 passes. If desired, the suction conduit may be given greater condens-v ing area by increasing its length by bends or coils either in the airor, as indicated in the drawing, in tank 3l. Any vapor thus condensed will be trapped in tank or chamber 33, and upon its accumulation in sui-li'-l cient amount to counterbalance the existing suction or upon the reduction of suction as by stoppage of the engine or opening the throttle, the liquid will flow through the communicating passages to tank 31, the valve 51 opening under hydraulic pressure land permitting the return of the condensate to the reservetank or lsupply reservoir.

Since the float valve opens toward the intake, it will tend to'be opened both under the influence of the suction and of the pressure of the vapors present in the radiator, that is due to the differential pressure into the area yof the valve seat, hence the open.-

ing movement will ltake place, when the engine is running, somewhat before it would be effected by the loss of buoyant effort or.

the weight. of the float due to the lowering .of the l1qu1d. The iuctations in level are therefore even less than those provided for ply the normal range of movement of the oat.

When the cooling medium ,is suliiciently heated, ebullition will occur to such an exv tent'that the vapor cannot be entirely drawn 0H through the comparatively restricted passage 32, in which case the liquid mayv fall to a level at or somewhat below that of the end opening of the overflow or supply pipe 30, and any excess vapor may escape freely through said pipe to the reserve tank, in which it willnormally condense, or, under extraordinary conditions, it may escape lto the atmosphere through the overflow pipe 48. A moderate amount of ebullitionmay occur without lowering the level of liquid below the transparent dome, when the latter is employed, the formation of bubbles be 'ing p ainly visible through the dome and thereby giving notice to theoperator of the physical condition of his cooling' system. This notice will be considerably in advancev of actual dangerous conditions due to bubbles forming with reater and greater frequency as the boiling point is approached.

There is considerable vaporization at temperatures` considerably below] the boiling 'point and' this effect is further accelerated by the reduced pressure in the radiator. This feature is particularly valuable when use is made of anti-freezing mixtures, such as alcohol mixtures, lwhere the boiling point is much lower than that of water, the cooling fluid generally employed. Such lowboiling constituents will be distilled olf and lost to the ordinary liquid circulating system during the normal operating temperatures of an enginek as indicated by a thermometer or other temperature responsive element, as the temperature at which serious loss of the liquid will take place is usually* unk'nown to the engine operator and inde-l terminate, due to material used and its c oncentration which again is usuallyv indeterminate. Ebullition andvaporization also take place at greater or less speed depending upon temperature and pressure. A sight lndication, therefore, vof/the action of the li uid itself is' the only convenient and true cr1terion which will permit the driver to y lill) position of visibility will give immediate indication of the existence of abnormal conditions.

While the transparent portionl of the liquid receptacle might .be varied widely 1n character, the dome-shaped form is 4preferred, since, by reason -of the refractive effect of the vcurved body, it reduces the apconduits and associated chambers is rendered relatively uniform notwithstanding the liuctuations in pressure conditions occurring in the source of suctionas in the engine intake. The constriction especially of conduit 34 prevents the occurrence in chamber 33 of abnormally highA vacuum corresponding to sudden increases in suction in the engine intake, thereby eliminating the probability of inducing further ebullition in the said chamber. -Since the operation of the mechanism requires onlythe removal from the system on starting of suicie'nt air torproduce the required sub-atmospheric pressure, any vapor which is drawn off being condensed inthe system, there will be no continuons flow to the-engine intake but merely an ebb and flow as suction conditions vary due to varying conditions of engine operation.

It will be seenfrom the foregoing description that the liquid supply system which I have .devised may be readily installed either as original equipmentfor as an accessory for vehicles already in service.- The working parts are. simple and easily and cheaply constructed and applied, the manner of mountmg and assembling the parts being such that they are readily accessible for removal, inspectlon, cleaning, or repair. Since the valve mechanism is mounted within the radiator casing or Within the indicator extension, no special fabricated housing is re-l quired, and its location in the upper part of the radiator permits sand, rust particles, or other sediment tov be removed by gravity from the vicinity of the valve.

The. indication is undisturbed by the ordinary interflow between 'the liquid cooling system and the reservoir due to .expansion and' contraction of the liquid caused by changes in temperature.

The indicationgivenby the device under normal conditions presents the appearance represented in Fig. 1, comprising a bubble in the upper ortion of the dome below which appears a and formed by the liquid, the color and character of which band will depend somewhat upon the nature and color of the float andthe presence of which may be rendered even more yapparent by a contrasting color 0n thev lower portion or cup of the indicator. The liquid itself may be. colored, if desired, to further-accentuate the contrasting features of the indicator. The distinctive appearance is such as to afford a clear indication at some distance from 'the device and in anydirection, as-from the station or seat of the operator or driver.- l

While I have'describedv the invention vin the foregoing embodiments as applied to the radiator of a motor vehicle engine, it 'will be understood that it may be-applied in other relationships wherever the novel features herein disclosed may be useful or desirable.

Many variations and n flodiications in details of construction may also 'made in addition to those herein described without departing from the spirit or sacrificing the advantages of the invention, and therefore I do not wish to be limited to the specific structure herein set forth except as required by the language of the appended claims. I claim:

1. In a cooling system for internal combustion engines for motor vehicles, the combination of a heat radiator having a transparent portion visible from the drivers station and 'means for supplying cooling liquid to said radiator to maintain the level of liquid within said radiator normally within said transparent portion during the operation of the engine.

2. In a radiator construction vfor motor vehicles, the combination of a radiator having a lling opening, a cap adapted to cooperate with saidv opening, said cap having a transparent dome, and means for normally maintaining the level of cooling liquid in said radiator within said dome during the operation of the engine.

3. In radiator construction, a radiator casing having a reduced upper portion provided with an opening, a cap for said opening, supply and suction conduitsand float valve mechanism Iremovable through said opening upon the removal of said cap and arranged to controlli-low through said con-v duits. l

4. In aliquid cooling system for internal combustion engines, a heat radiator having a filling tube and a cap therefor, a suction conduit having a ioat valve controlled ori- 'tice and supported between said filling tube and said cap. v

5. In a cooling system for internal combustion en es, al radiator, an auxiliary supply tan a conduit leading from said tank and having an end o ening in said radiator, and suction means or causing flow through said conduit for maintainin the level of cooling liquidwithin said ra iator normally during the operation of the engine above the end o ening of said conduit.

. 6. In a liqui coolingsystem for intern-al combustion engines, a. heat radiator an auxiliary supply tank, a supply conduit leadin from the radiator to said tank, and a suction conduit located within said supply7 conduit and arranged to communicate W th the upper portion of said radiator.

7. In a liquid cooling system for internal combustion engines, a radiator having the usual overflow pipe leading from the upper portion thereof, a reserve tank to which said ipe is connected, a suction conduit extending throu h said pi e tothe upper portion of the ra iator, an means'for controlling flow through said conduit.

8. In a cooling system forinternal -coinv bustion engines, a heat radiator, a reserve tank, a combined supply and overow conduit connecting the tank to the radiator, a

vsuction conduit leading from the upper part of' the radiator, and float-operated valve mechanism for controlling flow through said suction conduit, said valve mechanisml being so constructed and arranged that the valve tends to open under theinfluence of the suction in the suction conduit and the vapor pressure in the radiator, and close due to the buoyant eii'ort of the float.

9. In a cooling system for internal combustion engines, a Aradiator having a filler opening` and a gasket and a cap therefor, a reserve tank, a conduit connecting the tank to the radiator, a suction conduit extend- 'ing to the upper part? of said radiator with'- in lsaid filler opening, and float valve mechyanismsupported upon said gasket andhoused within said cap for controlling' flow l through said conduit.

10. In a cooling system for internal combustion engines, a radiator having a filler opening and a gasket and a cap'therefor, ai reserve tank, a conduit connecting said tank to said radiator, a suction conduit extending to -the upper art of `said radiator, a valve A arrangedto c ose the extremity of said coni duit'and opening in the direction vof flowl therein, and a float arranged to close said valve at its upper limit of movement, thev valve mechanism being mounted upon saidgasket and depending therefrom in the filler opening.

' 11. A liquid level indicator for Aliquid cooling systems .applicable to motor vehicles comprising a base adapted. to be applied to a radiator filling opening, a. trans-l parent dome supported upon said base, and means for controlling ysupply of cooling liquid to said radiator comprising fioati valve mechanism mounted within the enclo sure formed by said base. and. domek f i 12. A liquid level indicator for liquid dome supported upon said base and means for controlling supply of cooling liquid to said radiator comprising float valve mechanism mounted within the enclosure formed by said base and dome and in swivelled relation thereto.

13. The combination of a cooling system for internal combustion engines, a liquid supply reservoir having an overflow outlet, means for applying suction to reduce the gas pressure in the cooling system, means lfor condensing vapor withdrawn by such suction means, means for trapping the condensate and returning it to the reservoir, and means for preventing fiow from said reservoir to said suction means, comprising a liquid-sealed valve having its exit at a higher pointuin said reservoir than said overflow outlet. i

. I14:. In a. cooling system for liquid cooled internalcombustion engines, a radiator, a chamber having a sight opening, a liquid reservoir auxiliary to the radiator, means incident to the operation of the engine for supplying liquid from said reservoir to said v radiator `to maintain normally' the upper level of liquid in said radiator within predetermined limits with reference to said sight device, whereby said upper level may be ob. served through said sight device.

15. In combination with a liqud cooled l internal combustion engine and a sight device connected`to the cooling system thereof, means associated with saidfsight device an'd `system for normally maintaining the level v of the liquid in said system with its uppery level in predetermined relation to said sight device and for directing ebullitionfbubbles liquid.

from said system out through said portion of 16. The combination with the liquid cooling system of an internal combustion engine, a liquid lsupply reservoir open to atflow from said. reservoir to said system 4by atmospheric pressure, andV means for fcondensing the va or of said extracted gas during the operation of the engine.

17. The combination with the liquid cool- ,ing system of an internal combustion engine, a. liquid supply reservoir open to atinospheric pressure, and means-permitting liquid communication between them, of means for. reducing the pressure within the system below atmospheric by the extraction of .the surplus quantity of gas from a measured volume of gas confined and maintained therein during the normal-operation of the engine whereby. liquid' iscaused to fiow from said reservoir to said system by atmospheric pressure, and means. for condensing the vapor of said extracted gas and lretaining the condensation liquid in said cooling system during the operation of the engineo 18.l The combination with the liquid cooling system of an internal combustion engine, a liquid. supply reservoir open to atmospheric pressure, and means permitting liquid communication between them, of means for reducing the pressure withinv the system below atmospheric by the extraction of the surplus quantity of gas from a measured volume of gas confined and maintained therein during the normal operation of the engine whereby liquid is caused to flow from said reservoir to said system by atmospheric pressure, means for condensing the vapor of said extracted gas, during the operation of the engine, means for retaining v the condensation liquid and means for discharging said condensation liquid into said reservoir upon the restoration of latmospheric pressure in said retaining means.

19. The combination with the liquid cooling system of an internal combustion engine, a liquid supply reservoir open to atmospheric pressure, and means permitting liquid communication between them, of means for reducing the pressure within the sys' tem below atmospheric by the extraction of the surplus quantity of gas from a measured volume of gasconfined land maintained therein during the normal operation of the engine whereby liquid is caused to iow from said reservoir to said system by atmospheric pressure, means for condensing the vapor of said extracted gas, means for discharging said condensation liquid into said reservoir upon the restoration of. atmospheric pressure in said retaining means, a chamber having a transparent portion, in communication with said system and so located in respect to the liquid in the system, that a portion of the gas, maintained in the system, will be confined therein, and means for controlling the volume of the gas in said v chamber during the normal operation of the engine.

20. The combination with the liquid cooling system of an internal combustion engine, a liquid supply reservoir and a conduit permitting liquid communication between them, of a chamber comprising a space above the outlet of said conduit in communication with said system and so located in respect l to the liquid in' the system that a portion of the gas which may be in or generated in the system will be contained therein and means for maintainingv the volume of the gas contained in said chamber. les's than the totalvolume of said chamber, during'the lnormal operation of the engine.

21. The combinationY with the'liquid coole 4for maintaining the' volume of the gas -contained in said chamber less than the total volume of saidl chamber, said chamber having a. transparent portion so arranged that changes in the volume of the gas may be observed and indicate the conditions in the liquid cooling system during the operation of the engin 22. The combination with the liquid cooling system of an internal combustion engine,A a liquid supply reservoir and means per-4 mitting liquid communication between them, of a chamber in communication `with said' system andso located in respect to the liquid in the system that a portion of the gas which may be in or generated in the system will be contained therein and means for maintatining the volume of the gas contained in said'chamber less than the total volume of-said chamber, said chamber hav-v ing a transparent portion so arranged that changes in the volume of the gas may .be observed and indicate the conditions .in the liquid cooling system 4during the operation of the engine, said transparent portion being dome-shaped and confining saidl gas in its upper portion.

23. The combination with-the liquid cooling system of-an internal combustion engine, a liquid supply reservoir and means permitting liquid communication between them, of a chamber in communication with said system and so located in respect tothe liquid in the system that a portion of the gas which may be in or generated in the system will be contained therein and means for maintaining the volume of the gas contained in said chamber less than the total volume of said chamber, said chamber having a transparent, dome-shaped portion filled par.- tially with liquid and' partially with, gas during the normal operationv of the engine.

24. The combination with the liquid cooling system of an internal combustion engine, a liquid supply reservoir open to atmos pheric pressure, and means permitt1ngi11q uid communication between them, of means for reducing the pressure within the system below atmospheric by the extraction of extractedgas, and means for retaining' the aes4 condensate during the operation of the engine- ,25. The combinatlon withJ-the liquid cooling system of an internal combustion engine, a liquid supply reservoir open to atmospherlc pressure, and means permitting liquid communication between them, of means for reducing the pressure within the system `below atmospheric by the extraction of gas,

means for condensing the vapor of said extracted gas, means for retaining the condensation liquid, and means for discharging said condensate into said reservoir upon the 1U restoration of atmosphericv pressure in said retaining means.

In testimony whereof I affix my signature.

' JOHN M. LEA'. 

